The present invention relates to methods and apparatus for handling data at an intermediary computer. More specifically, this invention pertains to off-loading packet handling from a receiving or transmitting computer to the intermediary computer.
In TCP one of the parameters that limits packet transmission is the maximum segment size (MSS) of the packet through a computer network. The MSS is usually advertised between a client and a server, but may also be dictated by the network itself. That is, the packet size may be limited by the maximum transmission unit (MTU) of the network between the client and the server. As a result of these limits to the packet size, the client will typically send small data segments to meet these size requirements to the server.
When small segments are sent by a client within a computer network, the client TCP software allocates buffer space, forms a segment header, and computes a checksum for each segment. Additionally, client IP software encapsulates the segment in a datagram, computes a header checksum, and routes the datagram to the receiver software. The server IP software verifies the IP header checksum, and passes the segment to TCP software which then verifies the segment checksum, examines the sequence number, extracts the data, and places it within a buffer. Accordingly, smaller sized data packets or segments require significantly more processing resources by the receiving node (e.g., the server), as well as the client than larger sized packets.
Accordingly, there is a need for mechanisms for decreasing the processing load at a receiving or server processing node while meeting the network requirements for packets size between the sending processing node and the receiving processing node. Additionally, there is a need for reducing the load on such node when it is sending packets, as well as receiving them.